The present application relates to improvements to granular fuel burning boilers, such was wood pellet boilers, and burners therefor. In particular, the present application relates to an improved access door for the combustion chamber of wood pellet boilers and a means to dislodge residual ash and clinker from the grate of a combustion pot of a wood pellet boiler.
Granular fuel burning boilers have become increasingly common as a renewable source of domestic heat and/or hot water. An example of a granular fuel burning boiler is a wood pellet boiler. Wood pellet boilers typically comprise a hopper for storage of the pelletized wood fuel and a feeding means, such as an auger, for depositing said fuel into a burner or ‘combustion pot’ located within a combustion chamber where it is ignited and burned. Modern wood pellet boilers can operate automatically in that the pellet feed, ignition and combustion can be controlled by a programmable controller, with the rate of burn being adjustable to selected or pre-set temperatures. As the efficiency of wood pellet boilers increases, and with the advent of various government backed renewable heat incentives, their popularity and demand has also increased.
A significant problem with wood pellet burning boilers is the buildup of residual ash and clinker on the grate of the burner or combustion pot after combustion. Although a relatively small amount of ash is formed, it covers the spaces between the bars of the grate which in turn reduces the effectiveness of the combustion process. A further problem with wood pellet burning boilers is that access to the combustion pot for purposes of maintenance and cleaning is often difficult. This is a particular problem in domestic situations where a boiler is located at a position within a building near a wall or walls such that access on one or more sides is hampered. The present invention therefore attempts to mitigate these problems.